Dr Yiping Han is a PhD microbiologist. Dr Han's research evolves around understanding the virulence mechanism of F. nucleatum. Since joining the faculty at Case Western Reserve University, her research interest has expanded from basic science to include more clinically oriented studies. Dr Han and her colleagues recently developed a pregnant murine model and showed a causal relationship between F. nucleatum and preterm birth. Dr Han is using F. nucleatum as a model organism to investigate the correlation between oral health and preterm birth. She has research support from NIDCR, with an R03 award (DE 14447) to investigate the source of F. nucleatum infection in amniotic fluids in women in preterm labor, and an R01 award (DE 14924) to further characterize the FadA adhesin from this organism. Support from a K02 award will allow Dr Han to forego further grant applications for the near future and to avoid projected increase in teaching and administrative responsibilities. This will permit Dr Han to devote over 80% of her effort on her research program and her plans for re-education in dentistry and reproductive biology. Long term career goals are to become a well-rounded oral microbiologist competent in both basic science and translational research. The specific aims of this application are: (i) to characterize the FadA adhesin from F. nucleatum for its role in tissue cell attachment and invasion;(ii) to identify the host receptor for FadA and to characterize its role in F. nudeatum-hosl cell interactions;and (iii) to determine if women with amniotic fluid infections of F. nucleatum harbor the same species in the vaginal track, blood, or the oral cavity.